Fernando Alonso says he is staying very cautious about Ferrari's form despite the Italian squad dominating the first test of the year at Valencia this week.

The two-time champion joined the test today, taking over team-mate Felipe Massa at the wheel of the F10 car, after the Brazilian had topped the times on the previous two days.

Alonso was quick to find the pace with the car and ended up setting the fastest time of the week.

But despite Ferrari being quickest of all teams during the week, the Spaniard says it's still too early to judge the car's performance.

"No, I don't think so," said Alonso when asked by AUTOSPORT if Ferrari was clear favourite after the test.

"It's just the first day and as I said now at least for me the priority was getting completely comfortable. There are many things to discover for me, many things to learn.

"I think maybe if we topped the times the three days is related to fuel load or whatever, or maybe because it's true we are competitive. But before being competitive we need to make sure we do a lot of laps and that the car is strong and can finish all the grands prix. We are at that period of winter testing.

"We need to make the car very, very strong and until Barcelona or the last test at Jerez I think we will not look for the performance."

He added: "The first impression is always good. It was very good last year, and I was not in Q3 very often. For that I'm very, very cautious.

"It was a good first day, but also because I found the car very easy to drive because Felipe was running for two days and I've been taking this information from him which was a help."

The two-time champion, joining the historic Maranello squad from Renault, admitted it was an emotional day for him, as the Spaniard tested in front of nearly 40,000 fans.

"It was okay. It was an important day for me, first time in a Ferrari," he said. "A very emotional day this morning and also last night. I think I maximised the day in terms of laps and time on the track and I feel good.

"The car I have many things to adjust to, the seat, the pedals, the steering wheel, the helmet, which is a new brand for me. I never run with Brembo brakes, so that was a first for me as well. Many things to adapt, many things to check, but I had a good base in the car thanks to Felipe's job during the first two days.

"I think it was a really, really big help for me because I didn't lose time with the set-up or the car. I just concentrated in my comfort in the car because Felipe's set-up was good enough to keep running in the morning."

And Alonso insisted he is already feeling at home at Ferrari, saying he is enjoying the special atmosphere at the team.

"Yeah, I had time from day one at Ferrari. As I repeat many times, it's unbelievable the feeling here, the atmosphere, the passion of everybody. It's very nice to be in the garage, to speak Italian with all the mechanics.

"We have a kind of send of humour very similar to Spain so I felt very, very good so far. I keep enjoying life."